North Korea's only functioning reactor was a 5-megawatt facility at its main nuclear complex at Yongbyon, 60 miles north of the capital, Pyongyang. It could produce plutonium, a radioactive material used for nuclear bombs. It was shut down in July 2007, and North Korea has been taking steps to disable it - meaning the reactor cannot be easily restarted - under the watch of U.S. experts.
North Korea has also begun construction of a 50-megawatt reactor at Yongbyon but has made little progress. Construction of an even larger reactor nearby in Taechon has been stalled for years.
Under a 1994 U.S.-North Korea disarmament deal, two light-water reactors for generating power were to be built with international funding on North Korea's eastern coast near the town of Sinpo.
Construction was halted and the work abandoned after the outbreak of the latest nuclear crisis in late 2002.
RADIOACTIVE MATERIALS:
Experts believe North Korea may have produced up to 110 pounds
of plutonium. It is not known where it is being kept.
The U.S. has also accused North Korea of having a secret uranium enrichment program, which would provide another way to build nuclear weapons besides its known plutonium program. U.S. Secretary of State Condoleezza Rice said in early June that Washington was "troubled by additional information about North Korea's uranium enrichment capability" amid progress at the arms talks.
WEAPONS:
North Korea conducted a test detonation of a nuclear device in
October 2006, confirming it had the ability to make an atomic
weapon. It is believed to have enough plutonium to make as many as
10 nuclear bombs. North Korea is not believed to have a design for
a bomb that is small enough to be placed on top of a missile.
